In electrically powered vehicles, such as plug-in hybrid vehicles and pure electric vehicles, the batteries of the vehicles have to be charged regularly, preferably after each trip. For this purpose, the vehicle is connected to the charging infrastructure by means of a vehicle connection system.
For example, vehicle connection systems with a contact unit of the charging infrastructure that is provided on the ground are known. This ground contact unit, arranged on the ground, is physically contacted by means of a displaceable vehicle contact unit, which can move downwards from the underbody of the vehicle. This allows the vehicle to be electrically connected to the charging infrastructure.
These vehicle connection systems require a physical contact between the electrodes of the vehicle contact unit and the contact surfaces of the ground contact unit. With these systems, problems occur due to the contact surfaces of the ground contact unit and the electrodes of the vehicle contact unit becoming soiled or the vehicle contact unit not resting on the ground contact unit properly. Also, over time, an oxide layer will form on the electrodes or the contact surfaces, which increases the electrical resistance of the connection between the electrodes and the contact surfaces.
The soiling or the oxide layer on the contact surfaces or on the electrodes reduces the contact area and increases the resistance of the electrical connection, so that large power losses may occur during charging.
Also, liquids on the ground contact unit may cause leakage currents to occur between the electrode surfaces, resulting in power losses.
In addition, it is necessary that the vehicle contact unit is lowered evenly and parallel to the ground contact unit in order to allow optimum contacting. Otherwise, the electrical connection between the electrodes and the contact surfaces is impaired, and power losses are to be expected.